Instruction manual for sheet metal workers

This manual is intended as a textbook for apprentices in the sheet-metal working industry and for pupils in trade schools, continuation schools and other schools wishing to give thoro and adequate instruction in sheet-metal work.

Employers and labor organizations will find it a most valuable guide in giving a definite outline of the instruction the apprentice should receive. This assures a more rapid progress of the apprentice and makes it possible to determine accurately whether or not he is receiving the instruction to which he is entitled.

In the preparation of the manual we have followed the plan outlined in “How to Teach a Trade”. The plan is a very simple one. It seems perfectly obvious that the first step in teaching a trade ig to make a list of the things a man must know and must be able to do in order to be proficient in his trade. This gives us a list of the things we must teach him.

In making this analysis of the sheet-metal worker's trade we have endeavored to list the fundamental operations of the trade rather than the jobs of the trade. To list all of the jobs of the trade would be a great and useless task. To list the fundamental operations of the trade is a relatively simple task and adequately fulfills every requirement. If the jobs were listed it would be necessary to analyze each job into its fundamental operations in order to teach it. Since every conceivable job is made up of the operations of the trade, in various combinations, the simplest method of procedure is to analyze the trade for the operations involved and use these as the basis of analyzing the jobs of the trade. No job can be analyzed except in terms of the operations of the trade.

The list of operations constitute the alphabet of the trade. All jobs are made up of combinations of these operations just as words of our written language are made up of a combination of letters of the alphabet and with the same lack of consideration for the order in which they appear in the list.

The operations of the trade have been listed and definite directions given for performing each operation. These directions are followed by questions designed to make the learner think out the reasons why a thing is done in a certain way.

There is also a list of the topics of related trade information. These topics are treated in a brief and concise manner, in order to give the learner the necessary information in a readily available form.

Specific references are given in connection with the directions for each operation in order that the learner may get a more extended discussion of the subject if he desires to do so.

A number of valuable tables are given as well as problems in drafting, lay-out and construction together with methods of solving the problems.

Directions: Laying Flat Lock Roofing.

1. Fold the edges of the tin sheets in the shop.

2. Paint the underside of the tin sheets and stand them on edge against a wall to dry.

3. Examine the roof to see that it is free of projecting nails and lay special roofing paper over the surface which is to be covered with tin.

4. Start to lay the tin sheets at the lower left-hand corner of the roof.

5. Have the long edge of each sheet parallel with the eaves and extend the sheet 1 inch beyond the sheathing at the end of the roof.

6. Hook cleats 8 inches apart over the folded top and right-hand edges of each sheet and nail the cleats to the sheathing close to the edge of the tin sheet.

7. Lay the tin with the upper and right edges turned up to receive the next sheet.

8. Hook another sheet over the right edge, fasten it with cleats and continue across the roof parallel to the eaves.

9. Cut a sheet in half by cutting from bottom to top and start laying a second course at the left side. Start the third course with a full sheet and continue in this way to break joints on every course.

10. When tin in rolls is used for flat-lock roofing, turn the edges with roofing tongs. Adjust the gage on each end of the tongs to 1-2 inch, place the tongs over the edge of the tin on the right side at one end, rest your left foot on the metal sheet, hold the gages firmly against the edge and squeeze the handles together so that the blades will clamp against the metal.

11. Raise the tongs to turn the edge to an angle of about 45 degrees, move the tongs forward and continue this operation along the entire length of the edge, then work backwards and repeat the operation to turn the edge to a right angle, then work forward again and press the tongs over with your left foot to form a sharp angle ready for the lock seam.

12. Turn the sheet over and turn the other edge in the opposite direction to the first edge.

13. Lay the metal sheets parallel to the eaves and fasten them to the roof with cleats.

14. Clean the tin with a broom and pound the seams down with a mallet.

15. Apply rosin as a flux and with a hot soldering iron soak solder thru the seams.

16. Paint the tin roof with a coat of red mineral and pure linseed oil.

17. Notch and fold the narrow edges of the sheets.

18. Lock the sheets together in a long strip and soak the seams well with solder.

19. Paint the underside of the tin and lay the strips on racks to dry.

20. When the paint is dry, roll the strips into rolls and take them to the building.

21. Lay special roofing paper over the surface to be covered with tin.

22. Unroll the tin and turn the edges of the long strips with roofing tongs. For a one-inch standing seam use one pair of tongs set for 1 1/2 inches to turn one edge and another pair set for 1 1/4 inches to turn the other edge of each strip. Follow the operations as in paragraph II except that the edges should not be turned beyond a right angle.

23. Start at one end of the roof and lay the metal strips vertically. Turn the strips so that the open edges of the horizontal seams are at the bottom so that water will run over them without leaking thru. Extend the edges 1 inch beyond the edge of the sheathing.

24. Fasten the strips with cleats 12 inches apart.

25. Lay each strip against the previous strip, fasten it to the sheathing with cleats and continue until the surface is covered.

26. Break horizontal seams, that is do not have them come opposite each other.

27. To double-seam the standing edge use gage seamers. Place the larger seamer over the edges with the square blade against the smaller edge. Press the handles together to bend the larger edge to a right angle over the smaller edge. Move the seamer forward and continue this operation over the entire seam. Reverse the seamer and place over the edge the blade which is supported by a spring and with the left foot press the blade down to turn the edge completely over.

28. Use a smaller seamer and repeat the operations as in paragraph 27 to form a double seam.

29. To double-seam with a hand seamer, place the large side of the seamer against the smaller side of the standing edge and Hand Double with a mallet pound the metal over on the seamer to a right angle. Move the seamer forward and continue the operation the full length of the seam. Hold the larger side of the seamer firmly against the opposite side of the standing edge and with a mallet mash the turned edge flat against the standing edge.

30. Hold the smaller side of the seamer against the turned edge again and bend the edge over to a right angle, then hold the seamer against the other side and mash the turned edge flat.


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Instruction manual for sheet metal workers